Supervisory signal for telephone-exchange systems.



- No. 7|s,293. Patented Dec. [6 1902.

E c. E. scmsusn.

SUPERVISUBY SIGNAL FOB TELEPHONE EXCHANGE SYSTEMS.-

(Abplicatian filed Apr. 1, 1901.\

(No Modpl.)

RE IURN.

W/TNESSES:

a To whom it may concern:

' UNITED STATES PATENT OFFICE,

CHARLES E. SCRIBNER, OF CHICAGO, ILLINOIS, ASSIGNOR TO WESTERN ELECTRIC COMPANY, OF CHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS.

SUPERVISORY SIGNALFOR TELEPHONE-EXCHANGE SYSTEMS.

SPECIFICATION forming part of Letters Patent N0. 716,293, dated December 16, 1902.

Application filed April 1, 1901. Serial No. 63,883. (No model.)

Be it known that I, CHARLES E. SCRIBNER, a citizen of the United States, residing at Chicago, in the county of Cook and State of Illinois, have invented a certain new and useful Improvement in Supervisory Signals for Telephone-Exchange Systems, (Case No. 495,) of which the following is a full, clear, concise, and exact description.

My invention relates to a supervisory signal for telephone-toll lines, andhas for its object to provide a signal at thecentral office of a telephone-exchange by which the centraloflice operator may be informed of the condition of the telephone-toll device at the substation.

I will describe my invention more particularly byreference to the accompanying drawing, which is a diagram illustrating a telephone-line extending from a substation to a central office, with the operators switching apparatus at the central office, the system being equipped with the signal and circuits of my invention. I

The featureswhich I regard as new will be pointed out in-the appended claims.

The telephone-line extendsin two limbs 1 2 from the toll-station A to the central ofice B, where it terminates in the line-springs a 06 respectively, of the spring-jack a. The limb 2 of the line is connected at the central office through the armature and back contact of a cut-0E relay 1) and the winding of the line.- relay 0 with the free pole of the grounded line-batteryd. The line-relay 0 controls a subsidiary-line signal-lamp c in the usual manner. .The winding of the,cut-off relay 7) is included in agrounded conductor 3 from the test-ring a of the spring-jack. At the substation the usual telephone talking apparatus and signal-bell are included in bridges of the line-circuit, the bridge containing the talking apparatus being controlled by the usual telephone-switch. i

The tolldeviceat the substation has a coinchute e, adapted to receive coins of suitable size, and a-pivotedvalve or deflector-plate e, mounted underneath the lower end of said coin-chute and adapted to stop the coin in its downward course within the chute. The deflector-plate is adapted to be moved to either side to release the coin and direct it either into the cash-box or into a return-chute leading to the outside of the box.

A push-button f is provided, by which the subscriber may throw the deflector-plate e to the left to release the coin and cause it to return to the outside of the box. The subscriber may do this at any time before the coin has been disposed of. The valve is connected, by means of a link, with the pivoted armature-lever of the magnet g, and when the magnet is excited its armature in moving over throws the deflector-plate e to the right, so releasing the coin and guiding. it into the cash-box.

A switchlever it controls a grounded branch 4 from the limb 2 of the telephoneline, said grounded branch containing the helix of the magnet g. The switch-lever is provided with an arm which projects into the coin-chute in position to be engaged by a coin therein, so that when a coin is in the chute the grounded branch 4, containing the magnet g, is closed. The helix of magnet g is of high impedance, and the magnet is adjusted so that it will not respond to the battery-currents in the line, but will respond only to a special current of, say, one hundred and ten volts from the generator G at the central office.

The switchboard operator is provided with pairs of plugs and their associated cord-circuits for uniting any two lines by plugging into the spring jacks thereof. A pair of plugs kl is illustrated, each plug having tip, ring, and sleeve contacts, which are adapted to engage with the short and long line-springs and the test-rings, respectively, of the springjacks. The tips of the plugs are united by a conductor 5 of the cord-circuit, and, similarly, the rings are united through a cord conductor 6. i

A repeating coil is interposed in the plugcircuit in the usual manner, andabattery m is connected in a bridge between 'the'windings of the repeating coil. The pole of the battery which is connected with the cordstrand 5 is grounded, and the other or free pole is connected to the sleeves or third contacts of the plugs through supervisory-signal lamps, as usual. The cord-strand 6 may contain the usual supervisoryrelays n 11 between the free pole of the tacts of the plugs 7t Z, respectively, which relays control shunts about their respective supervisory-signal lamps.

A special supervisory relay is provided,

' having differential windings 0 0 which are x box.

included in the cord-strands 5 6, respectively. The relay is adapted when excited to close a local circuit containing a special supervisorysignal lampp. The windings 0 0 are of low resistance and impedance, so as not to interfere with the passage of telephonic currents.

When subscriber A desires a connection at the central office, he deposits in the coinchute e a suitable coin, which falls down until stopped by the deflector-plate e, in which position it causes the closure of the ground branch 4 from the line conductor 2. Circuit from the line-battery d is thus completed through the line-signal relay 0 to ground at the substation, the line-lamp c is lighted, and the operator observing the signal inserts her answering-plug in the spring-jack. The cutoff relay 1) is then excited by current from the batterym flowing to the third contact or sleeve of the answering-plug and thence to ground through the conductor 3, the line-signal apparatus being thus cut off. When the answering-plug is inserted in the spring-jack,current from the grounded battery m flows out over the cord-strand 6 and the line conductor 2 to ground by way of the branch 4 at the substation. The supervisory relay n is excited and shunts out its associated lamp. The winding 0 of the magnet 0 also receives current and causes said magnet to be excited, closing the local circuit, which includes the special signal-lamp 19, so that said lamp is lighted to indicate that the coin is still present in the coin-chute at the substation. A portion of the current from battery m instead of passing to ground at the substation by way of branch 4 returns to the central office over the'limb l of the telephone-line, which in eludes the winding 0 of relay 0; but so much current is diverted to ground at the substation that the two windings o' 0 do not balance one another, and the relay attracts its armature in consequence. When the connection asked for has been made, the operator presses the key g, which connects the generator G to the limb 2 of the telephone-line, so causing the excitement of the magnet g. The valve e is thereby thrown to the right and the coin released and guided into the cash- If, however, the desired connection cannot be made, as when the line called for is busy, the operator will tell the subscriber to press the buttonf, and his coin will be returned to him. The pressing in of the button f throws the deflector-plate to the left, releasing the coin and guiding it into the return-chute leading to the outside of the tollbox. As soon as the coin is released from battery and the ring-conthe chute the ground branch 4: is broken, and both windings 0 0 of the relay 0 in the plugcircuit receive equal current, so that the relay being difterentially wound is deenergized and breaks the local circuit containing the signal-lampp. The-differentially-wound signal-controlling device 0 thus serves to inform the operator of the condition of the toll device at the substation. If the subscriber attempts to get back his coin while the connection is being made, the release of the coin and consequent breaking of the ground branch 4 will cause the extinction of the signal-lamp p, and the operator will take this as a signal for disconnection and pull out the plugs.

My invention thus contemplates a metallic circuit between the substation and the central office, a source of current in a bridge of the circuit, one pole of said source of current being connected to ground or other returnconductor, a switch It at the substation. for grounding one of the line conductors, two

magnet-windings, one in each side of the metallic circuit, and a signal controlled through the agency of the two magnet-windings acting jointl Having thus described my invention, I claim as new, and desire to secure by Letters Patent, the following:

1. The combination with a metallic-circuit telephone-line extending from a substation to a central office, of a source of current in a bridge of the line, one pole of said source of current being connected to a return-conductor, a branch from one of the limbs of the telephone-line at the substation to the returnconductor, a switch controlling said branch, two magnet-windings, one in each limb of the metallic circuit, and a signal controlled by the differential effect of said windings, substantially as set forth.

2. The combination with a metallic-circuit telephone-line extending from a substation to a central office, of a source of current in a bridge of the circuit at the central office, one pole of said source of current being connected to a return-conductor, telephone apparatus,

in a bridge of the circuit at the substation, a branch to the return-conductor at the substation from the line conductor which is connected to the free pole of the source of current, a switch controlling said branch, and a signal-controlling instrument at the central office having two differential windings, one in each side of the metallic circuit, substantially as set forth.

3. The combination'with a metallic-circuit telephone-line extending from a toll-station to a central office, of a battery in a bridge of the line at the central oflice, one pole of the battery being grounded, telephone apparatus in a bridge of the line at the substation, a toll-box having a coin-chute and a switch adapted to be actuated by a deposited coin, mechanism whereby the subscriber may conthe coin, a ground branch trol the disposal of from one of the Iine conductors, controlled by the said coin-actuated switch, and a signal-controlling electromagnet having two differential windings, one in each of the line conductors, whereby the central-ofiice operator may be informed of the presence of a coin in the toll-box, as described.

In Witness whereof I hereunto subscribe my namethis 4th day of March, A. D. 1901.

CHARLES E. SORIB NER.

Witnesses:

ELLA EDLER, ADELL HOCKETT. 

